diff --git a/.drone.yml b/.drone.yml
deleted file mode 100644
index 4a2a84c06d..0000000000
--- a/.drone.yml
+++ /dev/null
@@ -1,35 +0,0 @@
-kind: pipeline
-name: fluentd-test-arm64-3-0
-
-platform:
-  os: linux
-  arch: arm64
-
-steps:
-- name: fluentd-test-arm64-3-0
-  image: arm64v8/ruby:3.0
-  commands:
-  - apt update
-  - apt -y install libgmp3-dev
-  - export BUNDLE_GEMFILE=$PWD/Gemfile
-  - gem update --system
-  - bundle install --jobs=3 --retry=3 --path=${BUNDLE_PATH:-vendor/bundle}
-  - bundle exec rake test
----
-kind: pipeline
-name: fluentd-test-arm64-2-7
-
-platform:
-  os: linux
-  arch: arm64
-
-steps:
-- name: fluentd-test-arm64-2-7
-  image: arm64v8/ruby:2.7
-  commands:
-  - apt update
-  - apt -y install libgmp3-dev
-  - export BUNDLE_GEMFILE=$PWD/Gemfile
-  - gem update --system
-  - bundle install --jobs=3 --retry=3 --path=${BUNDLE_PATH:-vendor/bundle}
-  - bundle exec rake test
diff --git a/.github/workflows/linux-test.yaml b/.github/workflows/linux-test.yaml
deleted file mode 100644
index f814623805..0000000000
--- a/.github/workflows/linux-test.yaml
+++ /dev/null
@@ -1,36 +0,0 @@
-name: Testing on Ubuntu
-
-on:
-  push:
-    branches: [master]
-  pull_request:
-    branches: [master]
-
-jobs:
-  test:
-    runs-on: ${{ matrix.os }}
-    continue-on-error: ${{ matrix.experimental }}
-    strategy:
-      fail-fast: false
-      matrix:
-        ruby-version: ['3.1', '3.0', '2.7', '2.6']
-        os: [ubuntu-latest]
-        experimental: [false]
-        include:
-          - ruby-version: head
-            os: ubuntu-latest
-            experimental: true
-
-    name: Unit testing with Ruby ${{ matrix.ruby-version }} on ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: ${{ matrix.ruby-version }}
-      - name: Install addons
-        run: sudo apt-get install libgmp3-dev libcap-ng-dev
-      - name: Install dependencies
-        run: bundle install
-      - name: Run tests
-        run: bundle exec rake test
diff --git a/.github/workflows/macos-test.yaml b/.github/workflows/macos-test.yaml
deleted file mode 100644
index 630b03de7a..0000000000
--- a/.github/workflows/macos-test.yaml
+++ /dev/null
@@ -1,34 +0,0 @@
-name: Testing on macOS
-
-on:
-  push:
-    branches: [master]
-  pull_request:
-    branches: [master]
-
-jobs:
-  test:
-    runs-on: ${{ matrix.os }}
-    continue-on-error: ${{ matrix.experimental }}
-    strategy:
-      fail-fast: false
-      matrix:
-        ruby-version: ['3.1', '3.0', '2.7']
-        os: [macos-latest]
-        experimental: [true]
-        include:
-          - ruby-version: head
-            os: macos-latest
-            experimental: true
-
-    name: Unit testing with Ruby ${{ matrix.ruby-version }} on ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: ${{ matrix.ruby-version }}
-      - name: Install dependencies
-        run: bundle install
-      - name: Run tests
-        run: bundle exec rake test
diff --git a/.github/workflows/windows-test.yaml b/.github/workflows/windows-test.yaml
index 1f43f18e57..937d69d481 100644
--- a/.github/workflows/windows-test.yaml
+++ b/.github/workflows/windows-test.yaml
@@ -1,4 +1,4 @@
-name: Testing on Windows
+name: Ruby 3.1 on Windows
 
 on:
   push:
@@ -13,34 +13,24 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby-version: ['2.7', '2.6']
+        ruby-version: ['3.1']
+        in_tail: [true, false]
         os:
           - windows-latest
         experimental: [false]
-        include:
-          - ruby-version: '3.0.3'
-            os: windows-latest
-            experimental: false
-            # On Ruby 3.0, we need to use fiddle 1.0.8 or later to retrieve correct
-            # error code. In addition, we have to specify the path of fiddle by RUBYLIB
-            # because RubyInstaller loads Ruby's bundled fiddle before initializing gem.
-            # See also:
-            # * https://github.com/ruby/fiddle/issues/72
-            # * https://bugs.ruby-lang.org/issues/17813
-            # * https://github.com/oneclick/rubyinstaller2/blob/8225034c22152d8195bc0aabc42a956c79d6c712/lib/ruby_installer/build/dll_directory.rb
-            ruby-lib-opt: RUBYLIB=%RUNNER_TOOL_CACHE%/Ruby/3.0.3/x64/lib/ruby/gems/3.0.0/gems/fiddle-1.1.0/lib
 
-    name: Unit testing with Ruby ${{ matrix.ruby-version }} on ${{ matrix.os }}
+    name: in_tail ${{ matrix.in_tail }}
     steps:
       - uses: actions/checkout@v2
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby-version }}
-      - name: Add Fiddle 1.1.0
-        if: ${{ matrix.ruby-version == '3.0.3' }}
-        run: gem install fiddle --version 1.1.0
       - name: Install dependencies
         run: ridk exec bundle install
-      - name: Run tests
-        run: bundle exec rake test TESTOPTS=-v ${{ matrix.ruby-lib-opt }}
+      - name: test in_tail
+        if: ${{ matrix.in_tail }}
+        run: bundle exec rake test TESTOPTS="-v --testcase='/(TailInputTest|IntailIOHandlerTest)/'"
+      - name: test without in_tail
+        if: ${{ !matrix.in_tail }}
+        run: bundle exec rake test TESTOPTS="-v --ignore-testcase='/(TailInputTest|IntailIOHandlerTest)/'"
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
deleted file mode 100644
index d1e0de3095..0000000000
--- a/.gitlab-ci.yml
+++ /dev/null
@@ -1,103 +0,0 @@
-.install-template:
-  before_script:
-    - gem update --system
-    - ruby -v
-
-.test-template:
-  before_script:
-    - gem install rake
-    - bundle install
-    - chmod 777 -R ./test
-
-stages:
-  - build
-  - tests
-
-2-6-6:
-  image: "ruby:2.6.6"
-  stage: build
-  extends: .install-template
-  script:
-    - bundle install --jobs=3 --retry=3
-  cache:
-    key: "$CI_COMMIT_REF_SLUG 2-6-6"
-    paths:
-
-2-7-2:
-  image: "ruby:2.7.2"
-  stage: build
-  extends: .install-template
-  script:
-    - bundle install --jobs=3 --retry=3
-  cache:
-    key: "$CI_COMMIT_REF_SLUG 2-7-2"
-    paths:
-
-3-0-0:
-  image: "ruby:3.0.0"
-  stage: build
-  extends: .install-template
-  script:
-    - bundle install --jobs=3 --retry=3
-  cache:
-    key: "$CI_COMMIT_REF_SLUG 3-0-0"
-    paths:
-
-rubyhead:
-  image: "ruby:latest"
-  stage: build
-  extends: .install-template
-  script:
-    - bundle install --jobs=3 --retry=3
-  cache:
-    key: "$CI_COMMIT_REF_SLUG latest"
-    paths:
-      - ./*
-
-2-6-6-test:
-  image: "ruby:2.6.6"
-  stage: tests
-  allow_failure: true
-  extends: .test-template
-  script:
-    - bundle exec rake test
-  cache:
-    key: "$CI_COMMIT_REF_SLUG 2-6-6"
-    paths:
-      - ./*
-
-2-7-2-test:
-  image: "ruby:2.7.2"
-  stage: tests
-  allow_failure: true
-  extends: .test-template
-  script:
-    - bundle exec rake test
-  cache:
-    key: "$CI_COMMIT_REF_SLUG 2-7-2"
-    paths:
-      - ./*
-
-3-0-0-test:
-  image: "ruby:3.0.0"
-  stage: tests
-  allow_failure: true
-  extends: .test-template
-  script:
-    - bundle exec rake test
-  cache:
-    key: "$CI_COMMIT_REF_SLUG 3-0-0"
-    paths:
-      - ./*
-
-rubyhead-test:
-  image: "ruby:latest"
-  stage: tests
-  allow_failure: true
-  extends: .test-template
-  script:
-    - bundle exec rake test
-  cache:
-    key: "$CI_COMMIT_REF_SLUG latest"
-    paths:
-      - ./*
diff --git a/lib/fluent/plugin/in_tail.rb b/lib/fluent/plugin/in_tail.rb
index deea7c9498..538f325cb5 100644
--- a/lib/fluent/plugin/in_tail.rb
+++ b/lib/fluent/plugin/in_tail.rb
@@ -1117,7 +1117,7 @@ def handle_notify
         end
 
         def open
-          io = Fluent::FileWrapper.open(@path)
+          io = File.open(@path, File::Constants::RDWR | File::Constants::BINARY | File::Constants::SHARE_DELETE)
           io.seek(@watcher.pe.read_pos + @fifo.bytesize)
           @metrics.opened.inc
           io
diff --git a/test/plugin/test_in_tail.rb b/test/plugin/test_in_tail.rb
index 36abb25a6c..0335384759 100644
--- a/test/plugin/test_in_tail.rb
+++ b/test/plugin/test_in_tail.rb
@@ -999,7 +999,7 @@ def test_rotate_file_with_write_old_and_no_new_file(data)
     end
 
     def sub_test_rotate_file(config = nil, expect_emits: nil, expect_records: nil, timeout: nil)
-      file = Fluent::FileWrapper.open("#{TMP_DIR}/tail.txt", "wb")
+      file = File.open("#{TMP_DIR}/tail.txt", File::Constants::WRONLY | File::Constants::CREAT | File::Constants::TRUNC | File::Constants::BINARY | File::Constants::SHARE_DELETE)
       file.puts "test1"
       file.puts "test2"
       file.flush
diff --git a/test/plugin/test_out_forward.rb b/test/plugin/test_out_forward.rb
index 53aca518c2..66a2776cc5 100644
--- a/test/plugin/test_out_forward.rb
+++ b/test/plugin/test_out_forward.rb
@@ -431,10 +431,12 @@ def try_write(chunk)
     ]
 
     stub(d.instance.ack_handler).read_ack_from_sock(anything).never
-    target_input_driver.run(expect_records: 2) do
-      d.run do
-        emit_events.each do |tag, t, record|
-          d.feed(tag, t, record)
+    assert_rr do
+      target_input_driver.run(expect_records: 2) do
+        d.run do
+          emit_events.each do |tag, t, record|
+            d.feed(tag, t, record)
+          end
         end
       end
     end
@@ -461,10 +463,12 @@ def try_write(chunk)
     ]
 
     stub(d.instance.ack_handler).read_ack_from_sock(anything).never
-    target_input_driver.run(expect_records: 2) do
-      d.run(default_tag: 'test') do
-        records.each do |record|
-          d.feed(time, record)
+    assert_rr do
+      target_input_driver.run(expect_records: 2) do
+        d.run(default_tag: 'test') do
+          records.each do |record|
+            d.feed(time, record)
+          end
         end
       end
     end
@@ -491,10 +495,12 @@ def try_write(chunk)
       {"a" => 2}
     ]
     stub(d.instance.ack_handler).read_ack_from_sock(anything).never
-    target_input_driver.run(expect_records: 2) do
-      d.run(default_tag: 'test') do
-        records.each do |record|
-          d.feed(time, record)
+    assert_rr do
+      target_input_driver.run(expect_records: 2) do
+        d.run(default_tag: 'test') do
+          records.each do |record|
+            d.feed(time, record)
+          end
         end
       end
     end
@@ -549,10 +555,12 @@ def try_write(chunk)
     ]
     # not attempt to receive responses
     stub(d.instance.ack_handler).read_ack_from_sock(anything).never
-    target_input_driver.run(expect_records: 2) do
-      d.run(default_tag: 'test') do
-        records.each do |record|
-          d.feed(time, record)
+    assert_rr do
+      target_input_driver.run(expect_records: 2) do
+        d.run(default_tag: 'test') do
+          records.each do |record|
+            d.feed(time, record)
+          end
         end
       end
     end
@@ -575,10 +583,12 @@ def try_write(chunk)
     ]
     # not attempt to receive responses
     stub(d.instance.ack_handler).read_ack_from_sock(anything).never
-    target_input_driver.run(expect_records: 2) do
-      d.run(default_tag: 'test') do
-        records.each do |record|
-          d.feed(time, record)
+    assert_rr do
+      target_input_driver.run(expect_records: 2) do
+        d.run(default_tag: 'test') do
+          records.each do |record|
+            d.feed(time, record)
+          end
         end
       end
     end